(a) Field of the Invention
This invention relates to an integral concrete foundation pierhead and jacking assembly and more particularly, but not by way of limitation, to a method of lifting a concrete foundation and/or floor system using the jacking assembly with the integral concrete foundation pierhead.
(b) Discussion of Prior Art
Heretofore, there have been a variety of foundation brackets, foundation jack assemblies and jack leveling systems for raising various types of foundation and concrete slabs. Also, the use of foundation brackets with steel pipe, concrete piers, helix steel piers and various other vertical support members installed into a ground surface adjacent to the foundation have been used in leveling foundation and floor systems.
None of the prior art foundation leveling systems provide the unique features, structure, method and advantages of the subject invention as described herein.
In view of the foregoing, it is a primary objective of the subject invention to provide a new and improved method of leveling and stabilizing a concrete foundation of a building structure and/or concrete floor system.
Another object of the new method is the use of a plurality of concrete pierheads which are integrated into the side of a concrete foundation which is corrosion protected. Also, an attached helix pipe pier or other type of vertical support member has fixity at each pierhead which provides a shorter xe2x80x9ccolumnxe2x80x9d length of the vertical support member.
Still another object of the method is the total cost of labor and materials of an installation is less due to a decreased cost of fabricated steel components and ease of installation.
Yet another object of the invention is the use of anchor bolts which serve as tensioning bolts. The bolts allow drawing and fixing of the helix pipe pier to the existing concrete. This feature eliminates undesirable movement by tightening nuts behind an anchor plate and against a sleeve through which the helix pier is jacked. Also, the movement of the pierhead can be controlled with additional embedded anchor bolts and reinforcement.
A further object of the invention is the use of a jacking assembly having a lower jacking plate located to allow full jacking force against the reinforced concrete pierhead. The width of the pierhead can be adjusted to suit required loads. The concrete pierhead is placed and cured to a desired strength. Each pierhead may include plastic and metal fibers, high strength cement and other strength enhancing measures. The pierhead can also be constructed of other flowable high strength material similar to concrete. Also, the anchor bolts and the jacking assembly parts can be readily designed to suit special loads and conditions. The pierheads can be adjusted to a selected elevation individually, progressively or synchronized as required with mechanical and/or hydraulic jacks. The proper loads can be adjusted by torquing nuts above the jacking plate.
Still another object of the invention is, following the lifting and tightening of bolts on the jacking plates, an annular space between an exterior sleeve around the top of the helix pipe pier or other vertical support member can be grouted with an expansive grout thereby increasing the overall strength of the pier or support member.
Furthermore, another object of the invention is a top concrete pour of the pierhead can be made of low strength concrete or a cover plate can be used to allow for future adjustments if necessary. In this application, the grouting between a sleeve and the top of the pier will require a lubricated material. Also, fill beneath the jacking plate should initially be a foam material. Further, a number of these types of pierheads can be installed in new structures to allow for expected level adjustments.
Yet another object of the invention is each pierhead can be designed to fit small and large loads, adjusted to the size and shape of the member it is to be connected to. The pierheads can also be adjusted to suit vertical, battered, tieback (lateral load resistance), horizontal ties, seismic resistance, seismic damper connections and connected various types of building structures where concrete sections and the like require alignment, moving together or separation. The unique pierheads with jacking assemblies provide a means to adjust and fasten together large and small structures and align the structures vertically, horizontally and at various angles thereto.
The subject method is used for forming a plurality of concrete foundation pierheads. Each pierhead is attached to a structure foundation and/or floor system. The pierheads are used for leveling the foundation and the floor system. The pierhead includes a jack assembly, which is used for jacking the pierhead on top of a helix pipe pier or vertical support member. The pier is driven into the ground surface exterior to the foundation or interior through a floor system. The floor system may be a concrete slab. When the method is used to form an interior pierhead, the steps include first removing a portion of the floor framing system and driving a helix pipe pier or vertical support member next to the interior foundation or through properly located openings in slab construction. Next, holes are drilled into the side of the foundation for receiving ends of epoxied dowels, bolt fasteners or rebar. When using a helix pipe pier, a top elevation of the pier is set to allow at least one more inch of rise than the correct floor level indicates. A plastic or metal pier cap pipe, having at least 8 inches in length is inserted into the ground and around the top of the pier or around the vertical support member. The jacking plates with all-thread bolts, rebar and dowels are set in place. The lifting procedure is then started.
A first pour of high strength concrete, for example, 4000 psi, is poured and allowed to cure. The bottom of the newly formed pierhead is 1 inch below the expected lift of the slab or foundation with a minimum of 4 inches below the slab for nuts with bolts to be cut off and additional leveling if required. After the pierhead has cured, the jacking is commenced. For light loads, nuts are tightened downwardly on a top jack plate with the top jack plate resting on top of the helix pipe pier and the sleeve. For heavy loads, a hydraulic jack may be used for loading against the top jack plate. As pressure is applied to the top jack plate, the pierhead is raised upwardly to a selected grade and the concrete foundation and/or floor structure is leveled. At this time, the nuts are tightened on top of the jack plate. The hydraulic jack is removed and the top of the all-thread bolts are cut off. Finally, a second concrete pour, for example, of 2000 psi concrete is applied to the top of the pierhead and allowed to cure thus providing a pierhead cap. Also, other fabricated caps can be used equally well in covering the top of the pierhead.
These and other objects of the present invention will become apparent to those familiar with helix pipe piers and other vertical support members used in stabilizing structure foundations and floor systems when reviewing the following detailed description, showing novel construction, combination, and elements as herein described, and more particularly defined by the claims, it being understood that changes in the embodiments to the herein disclosed invention are meant to be included as coming within the scope of the claims, except insofar as they may be precluded by the prior art.